Method and means for processing thermoplastic yarn



May 31, 1960 Filed April 18, 1958 D. STARKIE 2,938,258

METHOD AND MEANS FOR PROCESSING THERMOPLASTIC YARN 5 Sheets-Sheet 1 wea May 31, 1960 D. STARKIE 2,938,258

METHOD AND MEANS FOR PROCESSING THERMOPLASTIC YARN Filed April 18, 1958 5 Sheets-Sheet 2 l2 l4a I; F lg. 4.

6 AV/ r re ,4 Harm" D. STARKIE May 31, 1960 METHOD AND MEANS FOR PROCESSING THERMOPLASTIC YARN Filed April 18, 1958 5 Sheets-Sheet 3 )1 Q A O \m l l l I I J l I I l I I we M WM I fi M .d W m z I A Home y May 31, 1960 D. STARKIE 2,933,258

METHOD AND MEANS FOR PROCESSING THERMOPLASTIC YARN Filed April 18, 1958 5 Sheets-Sheet 4 /ZMW 3 A tlorney 'Filed April 18, 1958 METHOD AND MEANS FOR PROCESSING THERMOPLASTIC YARN 5 Sheets-Sheet 5 Fig. IO.

Inventor.- Za via/ Jfa-r-M'c;

bqAttorney METHOD MEAN FDR PROCESSING THERMUPLASTHI YARN David Starlrie, Somercotes, England, assignor to English Rose Limited Filed Apr. 18, 1958, Ser. No. 729,455

Claims priority, application Great Britain Apr. 27, 1957 14 Ciaims. (ill. 28-1) This invention refers to the manufacture of synthetic fiber yarn of the stretch type. Such yarns are finding increasing application in textiles and particularly in hosiery by reason of the additional elasticity, close fit, and warmth which they impart to a knitted garment, and the fact that they enable one garment to fit a range of sizes.

A number of synthetic fiber stretch yarns are already available to textile manufacturers. All are of the continuous filament type, containing either a single or a num ber of filaments, and all are able to be provided with stretch properties by reason of the thermoplastic nature of the materials from which they are made. Well-known examples of thermoplastic materials which are in common use as textile fibers are nylon and Terylene. By thermoplastic nature is meant the ability of the material .to retain the shape or form in which it has been held while at an elevated temperature.

The basis of manufacture of all stretch yarns is that the synthetic yarn is held in a crimped or folded condition by some means or other while at an elevated temperature and, on cooling, it remains crimped. If a crimped yarn is pulled, the crimps straighten out and the yarn extends in length; when the extending force is removed, the crimps reform and the yarn contracts in length. It is obvious that the type, shape, and size of the crimps will have a pronounced effect on the degree of extensibility and recovery, and the thermal insulating properties of the garment made from a stretch yarn.

The present invention as viewed from one aspect provides a method of manufacturing a synthetic fiber yarn of the stretch" type which comprises feeding a thermoplastic yarn to a crimping station at a repetitiously-fluctuating linear speed, receiving the yarn and continuing its travel beyond the station at a speed less than the mean linear speed so that the yarn adopts a crimped form at the crimping station and its continuing travel is in crimped form, and setting the yarn in that form.

As viewed from another aspect the invention also provides a method of manufacturing a synthetic fiber yarn of the stretch type which comprises crimping a thermoplastic yarn by feeding it to a crimping station through a vibrating device, receiving the crimped yarn at the crimping station and continuing its travel in crimped form,

- and setting it in that form.

The invention also provides a method of manufacturing synthetic fiber yarn of the stretch type, which comprises crimping a thermoplastic yarn by feeding it, at a repetitiously-fluctuating speed by means of a vibrating feeding device, between a pair of co-operating travelling surfaces which receive the crimped yarn from said device and hold it in its crimped form, and setting the yarn in that form by heat treatment.

The invention further provides apparatus for producing a crimped thermoplastic yarn, comprising yarn feed means for feeding the thermoplastic yarn to a crimping station at a repetitiously-fiuctuating linear speed, yarn conveying means for receiving the yarn and continuing its travel beyond the station at a speed less than the mean 'ice linear speed of the yarn, so that the yarn adopts a crimped form at the crimping station and its continued travel is in crimped form, and heating means for heat treating the travelling crimped yarn to set it in that form.

The invention still further provides apparatus for producing a crimped thermoplastic yarn comprising meansfor crimping the thermoplastic yarn which includes a vibrating device for feeding the yarn to a crimping station, conveying means for receiving the crimped yarn at the crimping station and continuing its travel in crimped form, and heating means for heat treating the travelling crimped yarn to set it in that form. I

Conveniently the vibrating device is of reciprocating resilient form to grip the yarn'in a feed stroke and slip on the yarn in a return stroke.

The above and other features of the invention set out in the appended claims are incorporated, by way of exemplification, in the constructions which will now be described, as specified embodiments with reference to the accompanying drawings in which:

Figure l is a diagrammatic view, inside elevation,1of

the main components of yarn crimping apparatus according to the invention,

Figure 2 is a plan view thereof;

Figure 3 is an enlarged view, in longitudinal section, of the crimping device,

Figure 4 is a diagram in side elevation of the main components of modified yarn crimping apparatus,

Figure 5 is an enlarged detail of a yarn feeding device of the modified apparatus,

Figure 6 is an end view of the yarn feeding device,

Figure 7 is a plan view of the yarn feeding device,

Figure 8 is a side view of a crimping unit of the modified apparatus,

Figure 9 is a side view of the modified apparatus,

Figure 10 is a front view of the modified apparatus.

The thermoplastic yarn 10 (for example nylon or Terylene) may be a monofilament or a plural filament yarn. It is drawn from a continuous source of supply and is advanced to a crimping station by a vibrating feeding device indicated generally by the reference '11. This feeding device 11 is vibrated longitudinally of the yarn and it operates to grip the yarn and to feed it during advance towards that station. Thus the yarn is fed to the station at a repetitiously-fluctuating linear speed. At the crimping station the yarn is received by means (bands 15a, 1511) which continues the travel of the yarn at a speed less than the mean linear speed at which the yarn is drawn off its supply and advanced to the crimping station. It therefore results that the yarn is caused to pile itself up into crimps at the crimping station. It

is received and its travel is continued in this crimped form (as illustrated at 10' in Fig. 2) and during this continued travel it is set in crimped form.

The vibrating device 11 consists in this example (but not in another example hereinafter described) of a tube 12 having a smooth bore 13 of a diameter sufficiently small to guide the yarn to be processed but sufliciently large to offer little or no resistance to the passage of the yarn. At its delivery end the tube is tapered as shown and is provided with two leaf springs 14a, 15b between the tips of which the yarn i0 emerges. These springs tend to grip the yarn. Thus as the device 11 is moved towards the crimping stationie. to the left in the drawings, the yarn is gripped by the springs 14a, 14b and is advanced towards the crimping station at a speed greater than that at which the means 15a, 15b can receive it, but when the device 11 moves in the opposite direction the springs slip over the yarn.

At the crimping station the yarn is received and gripped between the surface of two endless bands 15a, 15b travelling over rollers of which only one pair 16a, 16b is shown. The linear rate of travel of the bands is less than the speed at which the device 11 advances towards the crimping station, and indeed is less than the mean speed at which the yarn is drawn off its supply. As a result, on the advance of the device 11 (until the springs 14a, 14b nearly touch the bands) the yarn is folded at the crimping station into a sinuous form and in this form it is gripped between and held by the bands 15a, 15b. As the device 11 returns, the yarn is held by the bands and the device slips back over the yarn to an extent providing, beyond the delivery end of the device, adequate yarn to form the next fold upon the next advance of the device.

While it is thus held in its crimped or sinuous form the yarn is set; that is to say it is heated (preferably to a temperature above the boiling point of water) and is permitted to cool. For this purpose the bands 15a, 15b may be made of metal and may themselves be heated, for example electrically, by steam, hot air, infra-red radiation, or dielectric heating means. The yarn may be cooled following the heating.

It will be appreciated that the amplitude of the crimps or folds formed in the yarn 10 will be related to the length of stroke of the device 11; the pitch of the crimps will depend on the relation between the speed of vibration of the device 11 and the speed of the bands 15a, 1512. By varying these factors, changes in the crimped form and hence in the characteristics of the resultant stretch yarn can be made.

It will be appreciated that the end of the tube 12 is tapered and the springs 14a, 1412 given the shape shown in Figure 3 in order that the delivery end of the device 11 may fit closely into the nip between the bands. The device 11 may be vibrated by any suitable means, for example electromagntically or mechanically. An economic rate of production may call for supersonic vibration frequencies which can be provided by electromagnetic or magnetostrictive or any other means of generating supersonic frequencies. The axis of the bore 13 and the line along which the device is vibrated may be inclined at a slight angle to the nip of the bands 15a, 1511 but disposed in the same plane as the nip to ensure correct folding of the yarn. It may be advisable to reduce the rigidity of the yarn to enable it to take up the folded form more easily, for example by heating it as it is fed to or through the device 11.

It is not necessary to provide a separate pair of take-ofi bands such as 15a, 15b for each vibrating device 11 and for each yarn being processed. A number of vibrating devices may be operated side by side or constructed as a single unit each feeding its yarn to a common pair of take-off bands. This enables a plurality of crimped yarns each drawn from its own supply package to be processed side by side.

In the modified apparatus shown in Figures 4 to 10 the aforesaid tube 12 is dispensed with and is substituted by an upright 17 (see particularly Figures 4, and 6) made of stout spring material and having a guide hole 18 for the yarn. As shown in Figure 6 the hole 18 is conveniently provided at the root end of a slot 19 which opens into a side of the upright 17 to facilitate threading up, the yarn being first passed laterally along the slot 19 into the hole 18 and then passed laterally between the leaf springs 14a, 14b. The ends of these leaf springs are rounded as shown in Figure 7 to facilitate threading up. The leaf springs 14a, 14b (see particularly Figures 5 and 7) are attached to the upright 17 above and below the hole 18, and the upright 17 (Figure 4) is supported by the attachment of its lower end to the base 20' of a vibrator 20 which is of electromagnetic, magnetostrictive or any other known type. The operating arm 21 of the vibrator 20 is connected to an intermediate part of the upright 17 so as to effect reciprocatory flexings of it about its attachment to the vibrator base 20' and thereby 4 imparting the required yarn feeding vibrations leaf springs 14a, 14b.

Figure 8 shows how the vibrator feed means can form part of a crimping unit 40. In this unit 40, a lower support structure 22 for the lower endless band 15b also supports lower heating means 23a (adjacent the crimping station to set the yarn) and lower cooling means 24a with inlet and outlet 25a, 26a for cold water (remote from the crimping station to cool the set yarn). The upper endless band 15a, upper heating means 23 (adjacent the crimping station to set the yarn), and upper cooling means 24 with inlet and outlet 25, 26 for cold water (remote from the crimping station to cool the set yarn) are supported by an upper support structure 27 of said unit 40. This upper support structure 27 is hinged to the lower support structure 22 at a location 41 remote from the crimping station and consequently it can be swung upwardly with its supported parts to allow for threading up.

The lower endless band 15b travels over pairs of rollers 27, 27a and 27b, 270 which are spaced to accommodate the lower heating and cooling means 23a, 24a. Similarly the upper endless band 15a travels over pairs of rollers 28, 28a, and 28b, 280 which are spaced to accommodate the upper heating and cooling means 23, 24. The lower endless band 15b is driven through the intermediary of a sprocket chain 28, end sprocket wheels 29, and an intermediate sprocket wheel 30, and the upper endless band 15a is driven through the intermediary of these means and end inter-meshing pinions 31, 32, 33, 34 which engage and disengage upon displacement of the upper support structure 27 for threading up. The intermediate sprocket wheel 30 is driven by belt 31 and small pulley 31a from a suitable source of power such that the linear speed of the endless bands and consequently of the crimped yarn is less than the rate at which the yarn is fed to them.

to the There may be entry and exit guide plates 34, 35 in the unit 40 leading to and from the endless bands and each having a groove for the yarn.

Conveniently the apparatus is disposed in substantially upright manner as shown in Figures 9 and 10 from which it will be seen that the yarn passes upwardly from a supply 32, through a guide 38 and the crimping unit 40 and then through a guide 39 up to take off means 33. An electric motor 36 is provided to drive the belt 31 and there is a belt and pulley transmission 37 from this motor to the take up means.

In this example a number of the crimping units 40 are disposed in side by side spaced positions and sharing a common hinge pin 42 and take off means.

plastic yarn by feeding it to a crimping station through a vibrating device, receiving the crimped yarn at the crimping station and continuing the travel of the yarn in crimped form, and setting the yarn in that form.

3. A method according to claim 1 wherein the setting is efiected by heat treatment applied to the yarn as it leaves the crimping station; 7

v 4. A method according to claim 2 wherein the yarn, as it leaves the crimping station, is gripped between travelling surfaces and heated while so gripped.

' 5. A method according to claim 4 wherein the yarn is cooled following the heating while still gripped by the travelling surfaces.

6. A method of manufacturing synthetic fiber yarn of the stretch" type, which comprises crimping a theme plastic yarn by feeding it, at a repetitiously-fluctuating speed by means of a vibrating feeding device, between a pair of co-operating travelling surfaces which receive the crimped yarn from said device and hold it in its crimped form, and setting the yarn in that form by heat treatment.

7. Apparatus for producing a crimped thermoplastic yarn, comprising yarn feed means for feeding the thermoplastic yarn to a crimping station at a repetitiouslyfluctuating linear speed, yarn conveying means for receiving the yarn and continuing its travel beyond the station at a speed less than the mean linear speed of the yarn so that the yarn adopts a crimped form at the crimping station and its continued travel is in crimped form, and heating means for heat treating the travelling crimped yarn to set it in that form.

8. Apparatus for producing a crimped thermoplastic yarn comprising means for crimping the thermoplastic yarn which includes a vibrating device for feeding the yarn to a crimping station, conveying means for receiving the crimped yarn at the crimping station and continuing its travel in crimped form, and heating means for heat treating the travelling crimped yarn to set it in that form.

9. Apparatus according to claim 7 wherein the conveying means are endless travelling bands.

10. Apparatus according to claim 9, having the heating means and cooling means associated with said endless travelling bands.

11. Apparatus according to claim 8, wherein the vibrating device is of reciprocating resilient form to grip the yarn in a feed stroke and slip on the yarn in a return stroke.

12. Apparatus according to claim 11, wherein the vibrating device comprises a pair of leaf springs disposed substantially in V-formation, with the apex directed towards the conveying means, and a vibratory member carrying the springs.

13. Apparatus for producing a crimped thermoplastic yarn comprising means for crimping the thermoplastic yarn which means includes a vibrating device for feeding the yarn at a repetitiously-fiuctuating linear speed to a crimping station, co-operating endless travelling bands for receiving the crimped yarn between them at the crimping station and for holding it in crimped form while continuing its travel, and means for heat setting the yarn in crimped form.

14. Apparatus for producing a crimped thermoplastic yarn comprising means for crimping the thermoplastic yarn which means includes a vibrating device, having means for gripping the yarn on a feed stroke and for slipping on the yarn in a return stroke, for feeding the yarn at a repetitiously-fluctuating speed to a crimping station, means for vibrating said device to make feed strokes towards and return strokes away from the crimping station, yarn conveying and gripping means for receiving and gripping the crimped yarn at the crimping station and for holding it in crimped form while carrying it beyond the crimping station, and means for heat setting the yarn in crimped form.

References Cited in the file of this patent UNITED STATES PATENTS 1,978,407 Cadgene Oct. 30, 1934 2,262,268 Chatfield Nov. 11, 1941 2,394,165 Getaz Feb. 5, 1946 2,669,001 Keen Feb. 16, 1954 FOREIGN PATENTS 1,109,685 France Sept. 28, 1955 

1. A METHOD OF MANUFACTURING SYNTHETIC FIBER YARN OF THE "STRETCH" TYPE WHICH COMPRISES FEEDING A THERMOPLASTIC YARN TO A CRIMPING STATION AT A REPETITIOUSLYFLUCTUATING LINEAR SPEED, RECEIVING THE YARN AND CONTINUING ITS TRAVEL BEYOND THE STATION AT A SPEED LESS THAN THE MEAN 